This is an application for support for the Chemical and Molecular Pharmacology Training Program, a new venture undertaken in 2003. The sequencing of whole genomes and the initial characterization of myriad proteins and signal transduction pathways challenges us to unravel the design principles of cell signaling networks and understand how drugs can and do impinge upon them. This challenge will require the application of rigorous quantitative methods and concepts-those of physics, chemistry, engineering and informatics-to biomedical problems. It will therefore also require the recruitment of a different type of student to the field, a student with interests and abilities in quantitative science. The Chemical and Molecular Pharmacology training grant supports the rigorous training of quantitatively oriented students in the Chemical and Systems Biology Ph.D. program, which has evolved out of the Molecular Pharmacology Ph.D. program. The formal course work for the program includes not only core pharmacology disciplines like pharmacokinetics and pharmacodynamics, but also material drawn from the physical sciences. In addition, the students' research work is at the cutting edge of interdisciplinary science. It is our conviction that strong training in both biology and physical sciences is essential for training future leaders in chemical and molecular pharmacology